import { useEffect, useRef } from 'react'
import {
  Clock,
  Mesh,
  OrthographicCamera,
  PlaneGeometry,
  Scene,
  ShaderMaterial,
  Vector2,
  Vector3,
  WebGLRenderer,
} from 'three'

const vertexShader = `
precision highp float;

void main() {
  gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
}
`

const fragmentShader = `
precision highp float;

uniform float iTime;
uniform vec3  iResolution;
uniform float animationSpeed;

uniform bool enableTop;
uniform bool enableMiddle;
uniform bool enableBottom;

uniform int topLineCount;
uniform int middleLineCount;
uniform int bottomLineCount;

uniform float topLineDistance;
uniform float middleLineDistance;
uniform float bottomLineDistance;

uniform vec3 topWavePosition;
uniform vec3 middleWavePosition;
uniform vec3 bottomWavePosition;

uniform vec2 iMouse;
uniform bool interactive;
uniform float bendRadius;
uniform float bendStrength;
uniform float bendInfluence;

uniform bool parallax;
uniform float parallaxStrength;
uniform vec2 parallaxOffset;

uniform vec3 lineGradient[8];
uniform int lineGradientCount;

const vec3 BLACK = vec3(0.0);
const vec3 PINK  = vec3(233.0, 71.0, 245.0) / 255.0;
const vec3 BLUE  = vec3(47.0,  75.0, 162.0) / 255.0;

mat2 rotate(float r) {
  return mat2(cos(r), sin(r), -sin(r), cos(r));
}

vec3 background_color(vec2 uv) {
  vec3 col = vec3(0.0);

  float y = sin(uv.x - 0.2) * 0.3 - 0.1;
  float m = uv.y - y;

  col += mix(BLUE, BLACK, smoothstep(0.0, 1.0, abs(m)));
  col += mix(PINK, BLACK, smoothstep(0.0, 1.0, abs(m - 0.8)));
  return col * 0.5;
}

vec3 getLineColor(float t, vec3 baseColor) {
  if (lineGradientCount <= 0) {
    return baseColor;
  }

  vec3 gradientColor;
  
  if (lineGradientCount == 1) {
    gradientColor = lineGradient[0];
  } else {
    float clampedT = clamp(t, 0.0, 0.9999);
    float scaled = clampedT * float(lineGradientCount - 1);
    int idx = int(floor(scaled));
    float f = fract(scaled);
    int idx2 = min(idx + 1, lineGradientCount - 1);

    vec3 c1 = lineGradient[idx];
    vec3 c2 = lineGradient[idx2];
    
    gradientColor = mix(c1, c2, f);
  }
  
  return gradientColor * 0.5;
}

  float wave(vec2 uv, float offset, vec2 screenUv, vec2 mouseUv, bool shouldBend) {
  float time = iTime * animationSpeed;

  float x_offset   = offset;
  float x_movement = time * 0.1;
  float amp        = sin(offset + time * 0.2) * 0.3;
  float y          = sin(uv.x + x_offset + x_movement) * amp;

  if (shouldBend) {
    vec2 d = screenUv - mouseUv;
    float influence = exp(-dot(d, d) * bendRadius); // radial falloff around cursor
    float bendOffset = (mouseUv.y - screenUv.y) * influence * bendStrength * bendInfluence;
    y += bendOffset;
  }

  float m = uv.y - y;
  return 0.0175 / max(abs(m) + 0.01, 1e-3) + 0.01;
}

void mainImage(out vec4 fragColor, in vec2 fragCoord) {
  vec2 baseUv = (2.0 * fragCoord - iResolution.xy) / iResolution.y;
  baseUv.y *= -1.0;
  
  if (parallax) {
    baseUv += parallaxOffset;
  }

  vec3 col = vec3(0.0);

  vec3 b = lineGradientCount > 0 ? vec3(0.0) : background_color(baseUv);

  vec2 mouseUv = vec2(0.0);
  if (interactive) {
    mouseUv = (2.0 * iMouse - iResolution.xy) / iResolution.y;
    mouseUv.y *= -1.0;
  }
  
  if (enableBottom) {
    for (int i = 0; i < bottomLineCount; ++i) {
      float fi = float(i);
      float t = fi / max(float(bottomLineCount - 1), 1.0);
      vec3 lineCol = getLineColor(t, b);
      
      float angle = bottomWavePosition.z * log(length(baseUv) + 1.0);
      vec2 ruv = baseUv * rotate(angle);
      col += lineCol * wave(
        ruv + vec2(bottomLineDistance * fi + bottomWavePosition.x, bottomWavePosition.y),
        1.5 + 0.2 * fi,
        baseUv,
        mouseUv,
        interactive
      ) * 0.2;
    }
  }

  if (enableMiddle) {
    for (int i = 0; i < middleLineCount; ++i) {
      float fi = float(i);
      float t = fi / max(float(middleLineCount - 1), 1.0);
      vec3 lineCol = getLineColor(t, b);
      
      float angle = middleWavePosition.z * log(length(baseUv) + 1.0);
      vec2 ruv = baseUv * rotate(angle);
      col += lineCol * wave(
        ruv + vec2(middleLineDistance * fi + middleWavePosition.x, middleWavePosition.y),
        2.0 + 0.15 * fi,
        baseUv,
        mouseUv,
        interactive
      );
    }
  }

  if (enableTop) {
    for (int i = 0; i < topLineCount; ++i) {
      float fi = float(i);
      float t = fi / max(float(topLineCount - 1), 1.0);
      vec3 lineCol = getLineColor(t, b);
      
      float angle = topWavePosition.z * log(length(baseUv) + 1.0);
      vec2 ruv = baseUv * rotate(angle);
      ruv.x *= -1.0;
      col += lineCol * wave(
        ruv + vec2(topLineDistance * fi + topWavePosition.x, topWavePosition.y),
        1.0 + 0.2 * fi,
        baseUv,
        mouseUv,
        interactive
      ) * 0.1;
    }
  }

  fragColor = vec4(col, 1.0);
}

void main() {
  vec4 color = vec4(0.0);
  mainImage(color, gl_FragCoord.xy);
  gl_FragColor = color;
}
`

const MAX_GRADIENT_STOPS = 8

interface WavePosition {
  x: number
  y: number
  rotate: number
}

interface FloatingLinesProps {
  linesGradient?: string[]
  enabledWaves?: Array<'top' | 'middle' | 'bottom'>
  lineCount?: number | number[]
  lineDistance?: number | number[]
  topWavePosition?: WavePosition
  middleWavePosition?: WavePosition
  bottomWavePosition?: WavePosition
  animationSpeed?: number
  interactive?: boolean
  bendRadius?: number
  bendStrength?: number
  mouseDamping?: number
  parallax?: boolean
  parallaxStrength?: number
  mixBlendMode?: React.CSSProperties['mixBlendMode']
}

function hexToVec3(hex: string): Vector3 {
  let value = hex.trim()

  if (value.startsWith('#')) {
    value = value.slice(1)
  }

  let r = 255
  let g = 255
  let b = 255

  if (value.length === 3) {
    r = Number.parseInt(value[0] + value[0], 16)
    g = Number.parseInt(value[1] + value[1], 16)
    b = Number.parseInt(value[2] + value[2], 16)
  } else if (value.length === 6) {
    r = Number.parseInt(value.slice(0, 2), 16)
    g = Number.parseInt(value.slice(2, 4), 16)
    b = Number.parseInt(value.slice(4, 6), 16)
  }

  return new Vector3(r / 255, g / 255, b / 255)
}

export default function FloatingLines({
  linesGradient,
  enabledWaves = ['top', 'middle', 'bottom'],
  lineCount = [6],
  lineDistance = [5],
  topWavePosition,
  middleWavePosition,
  bottomWavePosition = { x: 2.0, y: -0.7, rotate: -1 },
  animationSpeed = 1,
  interactive = true,
  bendRadius = 5.0,
  bendStrength = -0.5,
  mouseDamping = 0.05,
  parallax = true,
  parallaxStrength = 0.2,
  mixBlendMode = 'screen',
}: FloatingLinesProps) {
  const containerRef = useRef<HTMLDivElement | null>(null)
  const targetMouseRef = useRef<Vector2>(new Vector2(-1000, -1000))
  const currentMouseRef = useRef<Vector2>(new Vector2(-1000, -1000))
  const targetInfluenceRef = useRef<number>(0)
  const currentInfluenceRef = useRef<number>(0)
  const targetParallaxRef = useRef<Vector2>(new Vector2(0, 0))
  const currentParallaxRef = useRef<Vector2>(new Vector2(0, 0))
  const targetGradientRef = useRef<Vector3[]>([])
  const currentGradientRef = useRef<Vector3[]>([])

  const getLineCount = (waveType: 'top' | 'middle' | 'bottom'): number => {
    if (typeof lineCount === 'number') return lineCount
    if (!enabledWaves.includes(waveType)) return 0
    const index = enabledWaves.indexOf(waveType)
    return lineCount[index] ?? 6
  }

  const getLineDistance = (waveType: 'top' | 'middle' | 'bottom'): number => {
    if (typeof lineDistance === 'number') return lineDistance
    if (!enabledWaves.includes(waveType)) return 0.1
    const index = enabledWaves.indexOf(waveType)
    return lineDistance[index] ?? 0.1
  }

  const topLineCount = enabledWaves.includes('top') ? getLineCount('top') : 0
  const middleLineCount = enabledWaves.includes('middle') ? getLineCount('middle') : 0
  const bottomLineCount = enabledWaves.includes('bottom') ? getLineCount('bottom') : 0

  const topLineDistance = enabledWaves.includes('top') ? getLineDistance('top') * 0.01 : 0.01
  const middleLineDistance = enabledWaves.includes('middle') ? getLineDistance('middle') * 0.01 : 0.01
  const bottomLineDistance = enabledWaves.includes('bottom') ? getLineDistance('bottom') * 0.01 : 0.01

  useEffect(() => {
    if (!containerRef.current) return

    const scene = new Scene()

    const camera = new OrthographicCamera(-1, 1, 1, -1, 0, 1)
    camera.position.z = 1

    const renderer = new WebGLRenderer({ antialias: true, alpha: false })
    renderer.setPixelRatio(Math.min(window.devicePixelRatio || 1, 2))
    renderer.domElement.style.width = '100%'
    renderer.domElement.style.height = '100%'
    containerRef.current.appendChild(renderer.domElement)

    const uniforms = {
      iTime: { value: 0 },
      iResolution: { value: new Vector3(1, 1, 1) },
      animationSpeed: { value: animationSpeed },

      enableTop: { value: enabledWaves.includes('top') },
      enableMiddle: { value: enabledWaves.includes('middle') },
      enableBottom: { value: enabledWaves.includes('bottom') },

      topLineCount: { value: topLineCount },
      middleLineCount: { value: middleLineCount },
      bottomLineCount: { value: bottomLineCount },

      topLineDistance: { value: topLineDistance },
      middleLineDistance: { value: middleLineDistance },
      bottomLineDistance: { value: bottomLineDistance },

      topWavePosition: {
        value: new Vector3(topWavePosition?.x ?? 10.0, topWavePosition?.y ?? 0.5, topWavePosition?.rotate ?? -0.4),
      },
      middleWavePosition: {
        value: new Vector3(
          middleWavePosition?.x ?? 5.0,
          middleWavePosition?.y ?? 0.0,
          middleWavePosition?.rotate ?? 0.2,
        ),
      },
      bottomWavePosition: {
        value: new Vector3(
          bottomWavePosition?.x ?? 2.0,
          bottomWavePosition?.y ?? -0.7,
          bottomWavePosition?.rotate ?? 0.4,
        ),
      },

      iMouse: { value: new Vector2(-1000, -1000) },
      interactive: { value: interactive },
      bendRadius: { value: bendRadius },
      bendStrength: { value: bendStrength },
      bendInfluence: { value: 0 },

      parallax: { value: parallax },
      parallaxStrength: { value: parallaxStrength },
      parallaxOffset: { value: new Vector2(0, 0) },

      lineGradient: {
        value: Array.from({ length: MAX_GRADIENT_STOPS }, () => new Vector3(1, 1, 1)),
      },
      lineGradientCount: { value: 0 },
    }

    if (linesGradient && linesGradient.length > 0) {
      const stops = linesGradient.slice(0, MAX_GRADIENT_STOPS)
      uniforms.lineGradientCount.value = stops.length

      // 初始化目标和当前渐变色
      targetGradientRef.current = []
      currentGradientRef.current = []

      stops.forEach((hex, i) => {
        const color = hexToVec3(hex)
        uniforms.lineGradient.value[i].set(color.x, color.y, color.z)
        targetGradientRef.current[i] = color.clone()
        currentGradientRef.current[i] = color.clone()
      })
    }

    const material = new ShaderMaterial({
      uniforms,
      vertexShader,
      fragmentShader,
    })

    const geometry = new PlaneGeometry(2, 2)
    const mesh = new Mesh(geometry, material)
    scene.add(mesh)

    const clock = new Clock()

    const setSize = () => {
      const el = containerRef.current!
      const width = el.clientWidth || 1
      const height = el.clientHeight || 1

      renderer.setSize(width, height, false)

      const canvasWidth = renderer.domElement.width
      const canvasHeight = renderer.domElement.height
      uniforms.iResolution.value.set(canvasWidth, canvasHeight, 1)
    }

    setSize()

    const ro = typeof ResizeObserver !== 'undefined' ? new ResizeObserver(setSize) : null

    if (ro && containerRef.current) {
      ro.observe(containerRef.current)
    }

    const handlePointerMove = (event: PointerEvent) => {
      const rect = renderer.domElement.getBoundingClientRect()
      const x = event.clientX - rect.left
      const y = event.clientY - rect.top
      const dpr = renderer.getPixelRatio()

      targetMouseRef.current.set(x * dpr, (rect.height - y) * dpr)
      targetInfluenceRef.current = 1.0

      if (parallax) {
        const centerX = rect.width / 2
        const centerY = rect.height / 2
        const offsetX = (x - centerX) / rect.width
        const offsetY = -(y - centerY) / rect.height
        targetParallaxRef.current.set(offsetX * parallaxStrength, offsetY * parallaxStrength)
      }
    }

    const handlePointerLeave = () => {
      targetInfluenceRef.current = 0.0
    }

    if (interactive) {
      renderer.domElement.addEventListener('pointermove', handlePointerMove)
      renderer.domElement.addEventListener('pointerleave', handlePointerLeave)
    }

    let raf = 0
    const renderLoop = () => {
      uniforms.iTime.value = clock.getElapsedTime()

      if (interactive) {
        currentMouseRef.current.lerp(targetMouseRef.current, mouseDamping)
        uniforms.iMouse.value.copy(currentMouseRef.current)

        currentInfluenceRef.current += (targetInfluenceRef.current - currentInfluenceRef.current) * mouseDamping
        uniforms.bendInfluence.value = currentInfluenceRef.current
      }

      if (parallax) {
        currentParallaxRef.current.lerp(targetParallaxRef.current, mouseDamping)
        uniforms.parallaxOffset.value.copy(currentParallaxRef.current)
      }

      // 平滑过渡渐变色 - 使用更慢的插值速度使过渡更平滑
      if (currentGradientRef.current.length > 0 && targetGradientRef.current.length > 0) {
        currentGradientRef.current.forEach((current, i) => {
          if (targetGradientRef.current[i]) {
            current.lerp(targetGradientRef.current[i], 0.02) // 从 0.05 降低到 0.02，使过渡更平滑
            uniforms.lineGradient.value[i].copy(current)
          }
        })
      }

      renderer.render(scene, camera)
      raf = requestAnimationFrame(renderLoop)
    }
    renderLoop()

    return () => {
      cancelAnimationFrame(raf)
      if (ro && containerRef.current) {
        ro.disconnect()
      }

      if (interactive) {
        renderer.domElement.removeEventListener('pointermove', handlePointerMove)
        renderer.domElement.removeEventListener('pointerleave', handlePointerLeave)
      }

      geometry.dispose()
      material.dispose()
      renderer.dispose()
      if (renderer.domElement.parentElement) {
        renderer.domElement.parentElement.removeChild(renderer.domElement)
      }
    }
  }, [
    enabledWaves,
    lineCount,
    lineDistance,
    topWavePosition,
    middleWavePosition,
    bottomWavePosition,
    animationSpeed,
    interactive,
    bendRadius,
    bendStrength,
    mouseDamping,
    parallax,
    parallaxStrength,
  ])

  // 单独处理渐变色更新，避免重新创建场景
  useEffect(() => {
    if (linesGradient && linesGradient.length > 0 && targetGradientRef.current.length > 0) {
      const stops = linesGradient.slice(0, MAX_GRADIENT_STOPS)
      stops.forEach((hex, i) => {
        const color = hexToVec3(hex)
        targetGradientRef.current[i] = color
      })
    }
  }, [linesGradient])

  return (
    <div
      ref={containerRef}
      className="w-full h-full relative overflow-hidden floating-lines-container"
      style={{
        mixBlendMode,
      }}
    />
  )
}
